• Title/Summary/Keyword: Cross effects

Search Result 3,398, Processing Time 0.029 seconds

An Experimental Study of the Influences of Basic Design Parameters on the Performance and the Noise Characteristics of Cross-flow Fans (직교류 홴의 설계인자가 성능 및 소음 특성에 미치는 영향에 대한 실험적 연구)

  • 구형모
    • Journal of KSNVE
    • /
    • v.10 no.3
    • /
    • pp.430-436
    • /
    • 2000
  • The cross-flow fans have been widely used to constitute the air moving systems in many air-ventilating and air-conditioning units. The cross-flow fan system has many design parameters which have crucial influence on the performance and the noise characteristics of the units. As a result there are many difficulties in the design stage of the system and the general design guide has not been sufficiently established yet. This study presents the experimental results of the parametric investigation of some chosen design parameters which are directly related to the shape of the stabilizer the profile of the scroll casing and the diffusion angle of the flow exit. The results are expressed in terms of the fan performance and the specific sound pressure level characteristics. Some parameters have been found to have crucial effects on the system performance/noise characteristics and should be considered with care in the design stage.

  • PDF

Dynamic Response Analysis of Composite H-type Cross-section Beams (복합재료 H-형 단면 보의 동적응답 해석)

  • Kim, Sung-Kyun;Song, Oh-Seop
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.20 no.6
    • /
    • pp.583-592
    • /
    • 2010
  • Equations of motion of thin-walled composite H-type cross-section beams exposed to concentrated harmonic and non-harmonic time-dependent external excitations, incorporating a number of nonclassical effects of transverse shear, primary and secondary warping, and anisotropy of constituent materials are derived. The forced vibration response characteristics of a composite H-type cross-section beam exhibiting the circumferentially asymmetric stiffness(CAS) configuration are exploited in connection with the structural bending-torsion coupling resulting from directional properties of fiber reinforced composite materials.

The Effect of Cross Education using Serial Reaction Time (연속반응시간과제를 이용한 교차훈련의 효과)

  • Choi, Jin-Ho;Park, So-Hyun
    • The Journal of Korean Physical Therapy
    • /
    • v.20 no.4
    • /
    • pp.15-20
    • /
    • 2008
  • Purpose: We investigated the effects of physical practice, mental practice, and cross education using serial reaction time (SRT). We recruited 21 right-handed healthy males and females who gave consent and had no clinical history for their upper limbs. Methods: The subjects were divided into three groups; actual practice (n=7), mental practice (n=7), and controls (n=7), who performed actual training, mental training, or no intervention respectively for three weeks. Super lab 4.0 displayed four symbols on the monitor and subjects pushed on the matching button, with reaction time assessed pre- and post-intervention. Results: Reaction time was significantly lower after actual or mental practice (p<0.05). Actual practice also decreased left hand reaction time. Conclusion: Actual practice and mental practice can improve motor learning, but mental practice is not sufficient for cross education.

  • PDF

Characteristics of Burr Generation and Deburring in Honing (호닝의 버 생성 분석과 제거가공에 관한 연구)

  • 최민석;김정두
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1996.11a
    • /
    • pp.100-104
    • /
    • 1996
  • This paper describes the characteristics of micro-burr formation in the cross hatch and deburring in honed surfaces. Two types of micro-burrs formed in the cross hatch were defined as upper edge burr (type A) and side edge burr (type B). The size of micro-burrs were measured for the honed surfaces of several cross hatch angle. Deburring mechanism and system using magneto-electrolytic process including the abrasive pad for mechanic deburring effects together were introduced. Deburring experiments and analysis were carried out to confirm the effectiveness of the deburring process.

  • PDF

Study on the Effect of Performance Factors on the Evaporator Using Liquid Desiccant Falling Flim for Dehumidification (습식건조제 이용 제습에서의 증발기 성능인자 영향 연구)

  • Park, M.S.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.7 no.3
    • /
    • pp.512-520
    • /
    • 1995
  • This study investigates the simultanceous heat and mass transfer between a falling desiccant film and air in cross flow at the interface. The application of this work is the optimization of falling film evaporators for use in potential hybrid air conditioning systems. The specific geometry considered is liquid TEG films falling along the vertical cooled surfaces of a channel with air in cross flow. The equations to describe the coupled heat and mass transfer between a falling desiccant film and air in cross flow for a falling film evaporator have been presented and solved numerically. The effects of important design and operating variables on the evaporator performance predicted by the parametric numerical analysis and suggestions for performance improvements of the evaporator are presented.

  • PDF

Dialysis in double-pass cross-flow rectangular membrane modules with external recycle for improved performance

  • Yeh, Ho-Ming
    • Membrane and Water Treatment
    • /
    • v.2 no.2
    • /
    • pp.75-89
    • /
    • 2011
  • The predicting equations for mass transfer rate in cross-flow rectangular dialyzers with double flow and recycle, have been derived by mass balances. The recycling operation has two conflicting effects. One is the desirable effect of the increase in fluid velocity, resulting in an increased mass transfer coefficient. The other is the undesirable effect of the reduction in concentration difference due to remixing, resulting in decreased mass-transfer driving force. In contrast a single-pass device without recycling, considerable improvement in mass transfer is achieved if the cross-flow rectangular dialyzer of same size is operated with double pass and external recycling. It is concluded that recycle can enhance mass transfer, especially for larger reflux ratio.

Simulations of Capacitive Cross-talk Effects on TFT-LCD Operational Characteristics (TFT-LCD 특성에 미치는 Capacitive Cross-talk의 영향에 대한 시뮬레이션)

  • 윤영준;정순신;김태형;최종선
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 1999.11a
    • /
    • pp.557-560
    • /
    • 1999
  • The design of large area thin film transistor liquid crystal displays (TFT-LCDs) requires consideration of cross-talks between the data lines and pixel electrodes. These limits are imposed by the parasitic capacitive elements present in a pixel. The capacitive coupling of the data line signal onto the pixel causes a pixel voltage error. In this study semi-empirical capacitance model which is adopted from VLSI interconnection capacitance calculations was used to calculate mutual coupling capacitances. With calculated mutual coupling capacitances and given image pattern, the root mean square(RMS) voltage of pixel is calculated to see vertical cross-talk from the first to the last column. The information obtained from this study could be utilized to design the larger area and finer image quality panel.

  • PDF

Experimental Study on the Aerodynamic Performance Characteristics for Various Design Factors in the Maximum Flowrate Range of a Cross-Flow Fan (관류홴의 최대유량역에서 설계인자 변화에 따른 공력성능 특성에 관한 실험적 연구)

  • Kim, J.K.
    • Journal of Power System Engineering
    • /
    • v.9 no.3
    • /
    • pp.44-49
    • /
    • 2005
  • The aerodynamic performance of an indoor room air-conditioner using a cross-flow fan is strongly influenced by the various design factors of a rear-guider and a stabilizer. The purpose of this study is to investigate the effects of a rear-guider and a stabilizer on the aerodynamic performance in the maximum flowrate range of a cross-flow fan. The design factors considered in this study are a rear-guider clearance, a stabilizer cutoff clearance, and a stabilizer setup angle, respectively. Aerodynamic performances including maximum flowrate and power show the biggest magnitude distribution in the case of $45^{\circ}$, the stabilizer setup angle as well as nearly similar magnitude distribution regardless of the stabilizer cutoff clearances. Moreover, the more a rear-guider clearance increases, the more the magnitude of maximum flowrate and power increases.

  • PDF

Conscientization and the Discursive Construction of Identity Across cultures: Using Literacy Autobiography as a Reflective and Analytical Tool

  • Pederson, Rod
    • Cross-Cultural Studies
    • /
    • v.20
    • /
    • pp.149-182
    • /
    • 2010
  • This paper reports on an ongoing study that utilizes the literacy autobiographies of 10 Asian and 10 Western graduate students from TESOL Masters programs in Korea and America as data for a cross cultural study on the discursive process of identity formation and the development of critical consciousness (Freire, 2000). While the data suggests similarities and differences between cultures in terms of the effects of education, social relationships, media, and religion, no definitive claims may be made due to the small size of the research corpus. However, analysis of the data revealed that only four of the narratives could be judged as engaging in critical introspection of individual subjects systems of knowledge, values, and beliefs, as opposed to the other narratives that were primarily descriptive of individual personal experiences. As such, this study found that while the willingness and ability to engage in the critical practices which lead to the development of a critical consciousness are similar across cultures, they may be mediated by the literacy practices inscribed in education, media, and other social practices.

Hydrophobic modification of PVDF hollow fiber membranes using polydimethylsiloxane for VMD process

  • Cui, Zhaoliang;Tong, Daqing;Li, Xue;Wang, Xiaozu;Wang, Zhaohui
    • Membrane and Water Treatment
    • /
    • v.10 no.4
    • /
    • pp.251-257
    • /
    • 2019
  • Fabricating hydrophobic porous membrane is important for exploring the applications of membrane distillation (MD). In the present paper, poly(vinylidene fluoride) (PVDF) hollow fiber membrane was modified by coating polydimethylsiloxane (PDMS) on its surface. The effects of PDMS concentration, cross-linking temperature and cross-linking time on the performance of the composite membranes in a vacuum membrane distillation (VMD) process were investigated. It was found that the hydrophobicity and the VMD performance of the PVDF hollow fiber membrane were obviously improved by coating PDMS. The optimal PDMS concentration, cross-linking temperature and cross-linking time were 0.5 wt%, $80^{\circ}C$, and 9 hr, respectively.